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    在线超滤-离子色谱法同时测定面粉中3种阴离子

    Simultaneous Determination of 3 Anions in Flour by IC with Inline Ultra-Filtration

    • 摘要: 采用在线超滤-离子色谱法同时测定面粉中BrO3-、NO2-、NO3- 3种阴离子的含量。10.00 g样品用水超声提取30 min,定容为100 mL,离心分离,取上清液通过0.22 μm在线超滤系统进行预处理。分取20 μL进样,经Metrosep A Supp 7-250阴离子分析柱和Metrosep A Supp 4/5 Guard 保护柱分离,以3.6 mmol·L-1碳酸钠溶液为流动相进行淋洗,采用抑制电导检测器进行检测。BrO3-、NO2-和NO3-分别在0.20~10.0 mg·L-1,0.02~2.00 mg·L-1和0.25~30.0 mg·L-1范围内呈线性关系,检出限(3S/N)在0.20~2.50 mg·kg-1之间。应用此方法分析了3个面粉样品,并以此为基体,用标准加入法进行回收试验,测得回收率在89.0%~110%之间,测定值的相对标准偏差(n=6)在2.2%~4.6%之间。

       

      Abstract: IC with inline ultra-filtration was applied to simultaneous determination of BrO3- , NO2- and NO3- in flour. The sample (10.00 g) was extracted ultrasonically with water for 30 min and the suspension was made up to 100 mL and centrifuged. The supernatant was filtered with the 0.22 μm inline ultra-filtration system. Twenty μL of the filtrate were separated on Metrosep A Supp 7-250 separation column and Metrosep A Supp 4/5 Guard protective column, using 3.6 mmol·L-1 Na2CO3 solution as mobile phase. Inhibitory conductivity detector was adopted in the determination. Linear relationships were kept between values of peak area and mass concentration of BrO3- , NO2- and NO3- in the ranges of 0.20-10.0 mg·L-1, 0.02-2.00 mg·L-1 and 0.25-30.0 mg·L-1 respectively, with detection limits (3S/N) in the range of 0.20-2.50 mg·kg-1. Three flour samples were analyzed by this method, and recovery was tested by standard addition method, giving values of recovery and RSD′s (n=6) in the ranges of 89.0%-110% and 2.2%-4.6% respectively.

       

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